1. Field of the Invention
This invention relates generally to a papermaking apparatus, and more particularly to a papermaking apparatus that can manufacture paper having good fiver texture. This invention also relates to a multi-layer paper forming apparatus having a plurality of such papermaking apparatuses.
2. Description of the Prior Art
A conventional type of papermaking apparatus basically comprises a flow box 32 for feeding paper stock to the wire-screen cylinder 31, a wire-screen cylinder 31 for dewatering the paper stock, and a couch roll 33 for forcing an endless felt couch 34 onto the wire-screen cylinder 31 to transfer a wet paper web to the bottom surface of the endless felt couch 34 to feed to the succeeding process, as shown in FIG. 1.
In such a conventional type of papermaking apparatus, the paper stock injected from the flow box 32 is dewatered by the wire-screen cylinder 31, and then the endless felt couch 34 is forced onto the wire-screen cylinder 31 by the couch roll 33. As pulses are generated by the pressure of the couch roll 33 exerted onto the endless felt couch 34, shear force is applied to dewater the paper stock, with the water draining inside the wire-screen cylinder 31. As a result, a wet paper web is produced and transferred to the bottom surface of the endless felt couch 34.
In the conventional type of papermaking apparatus, when paper stock is fed from the flow box 32 to the wire-screen cylinder 31, a fiber texture of paper is already formed but only to an insufficient degree. The fiber texture is therefore modified later by the shear force based on pulses caused by the pushing force of the couch roll 33.
The aforementioned conventional type of papermaking apparatus has the following problems.
(1) The number of pulses is few because pulses are generated at only one location. Consequently, the fiber texture formed by the flow box 32 is not adequately modified, and a good texture cannot be obtained.
(2) At higher speeds, the wet paper web tends to disintegrate at the contact area of the couch roll 33, making it impossible to increase the amount of deposition of the wet paper web per wire-screen cylinder, and accordingly the amount of paper stock to be fed. As a result, it is difficult to form a thick paper web.